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The K7RA Solar Update

A Solar Cycle 23 spot appeared for two days -- April 29-30 -- in an area that soon rotated out of view. Sunspot numbers were 15 and 12, but for the last seven days, we haven't seen any spots. This may end soon -- we get the advance word because of the STEREO mission, which is gradually able to see more and more of the sun not visible from Earth. On May 5-6, the STEREO B satellite was able to see an eruption from an active region around the eastern edge of the Sun, outside of our view. If sunspots emerge, they will be Solar Cycle 24 spots, due to their relatively high latitude.

Sunspot numbers for April 30-May 6 were 12, 0, 0, 0, 0, 0 and 0 with a mean of 1.7. The 10.7 cm flux was 69.4, 68.5, 68.3, 68.6, 68, 68 and 68.7 with a mean of 68.5. The estimated planetary A indices were 3, 5, 5, 5, 4, 2 and 6 with a mean of 4.3. The estimated mid-latitude A indices were 2, 2, 3, 2, 2, 2 and 6 with a mean of 2.7.

Tuesday morning, May 5, Red Haines, WO0W (his call is easy to confuse -- it is W-Oh-Zero-W) of La Crescent, Minnesota, wrote that HF conditions had improved over the past few days. He noted that he was hearing more of the worldwide NCDXF beacons on 14.100 MHz than recently, and that x-ray flux had also increased. Red mentioned that x-ray flux (an index of energy from the sun in the x-ray portion of the spectrum) is a better real-time indicator of the current state of the ionosphere than daily sunspot numbers or solar flux: "X-ray energy is a primary cause of ionization, which supports HF propagation."

If you go here, you can see the current and recent x-ray flux. Click on the graph for a better view. Red noted significant recent bursts of energy during and after recent sunspot activity on April 30 and May 1. You can here to see this -- click on the 20090501_xray.gif link. Other interesting dates are January 9-10 and February 10-13, also accessible from that same page that includes all of the plots for 2009.

The NOAA SWPC page here has links for a number of useful monitors for x-rays and magnetic indices, including a D-region absorption prediction for when conditions get rough.

Red likes to monitor beacons for a real-time indicator of propagation, using a tool called BeaconSee that creates an ongoing record of propagation on any HF band.

David Steels, VE3UZ, of London, Ontario, has a spreadsheet and graph showing monthly averages of solar flux values during solar minimums. He overlaid four solar minimums, lining up start dates for each cycle, and believes that his curves match a start date of September 2008 for Solar Cycle 24.

E-skip reports continue for 6 and 10 meters. Last Saturday, May 2, Trent Fleming, KG4ZDM, of Germantown, Tennessee (EM55), worked UT1FG/MM in EL33 and NP4A in FK68 on 6 meters. He said he heard many other stations, but shut down early due to an approaching storm.

Dan Van Orden, N7AQX, of Emporia, Kansas, had fun on 10 meter CW on May 3-4. Dan wrote, "On May 3, 1642 UTC, AJ4SF responded from Cameron, North Carolina with a 589 signal strength. A few minutes later, I tried several times to connect with KJ4RV. His signals were down to at least 339 at the time. This seems strange in that both stations are in the same vicinity. Of course antennas and location could have been the difference. On May 4, I heard several low power beacon stations from California. These beacons are hardly ever heard here in Kansas. They remained throughout the day. The band seemed to have gone west, since no beacons were heard from the Eastern USA. That in itself seems kind of strange. Beacons from Colorado and New Mexico were also heard, along with the California beacons. I finally worked K7DRA/5 in El Paso, Texas on 10 meter CW and got a 569 signal report.Looks like the band is changing after months of wintertime silence".

Bob Voss, N4CD, of Plano, Texas, sent in many comments about 10 meters last weekend, which he said was when the 10-10 club held their CW and digital contest. The comments were from people he worked and from an e-mail reflector. All reported strong activity on 10.

Vince Varnas, W7FA, of Portland, Oregon, reported a great 10 meter opening on Tuesday, May 5. He wrote, "I had a pile up of JAs on me for 90 minutes from 2312-0040 UTC. I worked 32 JAs before I had to go to dinner. I must have left about 5 or 6 on frequency, still calling. Sigs mostly S-9. Probably multi-hop Es, but it could have been F2, though".

Chip Margelli, K7JA, of Garden Grove, California (DM03), wrote: "Six meters has been opening up, marginally, across the Pacific. K6QXY was the first to make it across to Man, JL8GFB, on May 5 at 2330 UTC. Three other W6/7 stations made it on that day. Yesterday (May 7 UTC) I had a QSO with Man at 0018 UTC. Signals were 559 at the time, and Man peaked at about 579 later. On the same day (May 6 here on the West Coast), Johnny, KE7V, worked 20 JA stations, and several other Pacific Northwest stations worked several JAs each. Here in Southern California, N6KK and N6HC also worked JL8GFB on the afternoon of May 6; this was Arnie's, N6HC, first JA QSO on 6 meters. Audio clips of these and other QSOs made by JL8GFB are on his Web site. I run 200 W into a 9-element OWA antenna at about 75 feet".

That's all for this week. There were many other e-mails and subjects left unreported, but we had to stop somewhere, and this is it

Amateur solar observer Tad Cook, K7RA, of Seattle, Washington, provides this weekly report on solar conditions and propagation. This report also is available via W1AW every Friday, and an abbreviated version appears in The ARRL Letter. Check here for a detailed explanation of the numbers used in this bulletin. An archive of past propagation bulletins can be found here. You can find monthly propagation charts between four USA regions and 12 overseas locations here. Readers may contact the author via e-mail.